Objectors say the postcard would cost an "indecent" amount

The Postcard to Wales is one of three designs chosen to mark key entry points into the country, and would straddle the A550 in Flintshire.

Objectors launched a petition on the Downing Street website, claiming the 36m (118ft) tall and 76m (249ft) wide design was "hideous".

Project organisers Landmark Wales said it was aware of the petition.

A spokesman added they would be interested to see how many signatures the petition attracted.

Widely advertised

Anna Liu, of London-based architects Tonkin Liu said when the design was revealed that it would be made of a transparent woven fabric, that would allow light to flow through.

Inside, there would be enough room for facilities such as a bookshop.

She said: "The motorway is coming towards the river. A lot of people come towards the river and don't realise it. We wanted to make that much more of an experience, make this picture of Wales come out of the river."

The petition - which had 38 signatures by 1130 BST on Monday - said: "This art project is to cost an indecent amount of money (�18m) and was very poorly advertised in giving people the chance to object.

We will be very interested in the level of support it receives Landmark Wales

"The majority of people on Deeside do not want this hideous 'art' to be built in our area - at least those that knew about it."

The postcard design would rise from the River Dee, forming a tunnel across the A550, which is the main road into north Wales.

Mark Tami, MP for Alyn and Deeside, has also voiced concerns about the design, claiming a memorial to local heroes would have been more appropriate.

The design was chosen along with two other finalists - a giant red "cloud" planned for the second Severn crossing, and three granite pillars at Holyhead harbour on Anglesey.

Landmark Wales - which wanted artworks to signify the passage from one country to another - is now seeking �13.5m of Lottery funding towards the �18m total bill.

A spokesman said: "We will be very interested in the level of support it [the petition] receives as it will assist us in our ongoing public consultation on Landmark Wales in general and the proposed Postcard to Wales project in Flintshire."

The spokesman said the Flintshire project had been widely advertised in the area.

He added that local communities would help with the development of the three landmarks, if they received funding.

Downing Street introduced e-petitions to its website in November 2006 to encourage campaigners.